Various types of corner guard systems have been utilized in the past to protect the corner of an implement such as a loader bucket. These corner guard systems normally include a replaceable corner tooth that is expected to withstand relatively large working forces during normal operation. The releasable corner tooth may be of the unitooth type in which the portion that engages the ground and the portion that is secured to the implement are one and the same or it may be the type in which an adapter is secured to the implement while a replaceable tip is secured to the leading end of the adapter and is operative to engage the ground. Most of these designs are releasably secured to the implement by one or more bolts and have load transferring pads arranged on the replaceable corner tooth such that forces can be transmitted therethrough to the implement. It is desirable to have a simple design but to also insure that the optimum conditions are maintained in transferring the forces from the leading end of the tip into the implement itself. It is also desirable that the replaceable corner tooth be securely connected to the implement and not be allowed to move during operation. It has been found in some past designs that since the elements that form the corner of the implement are welded one to the other that it is difficult to hold reasonable tolerances between the bottom of the implement and the holes that are used to secure the corner tooth to the implement. Therefore, in this type of design, it is beneficial not to have areas on the replaceable corner tooth that transfer loads directly to the bottom of the hardened cutting edge.
Another problem that has been experienced with some of the previous designs is that in order to effectively transfer the loads from the leading edge of the tip into the implement, the replaceable corner tooth becomes very complicated and extremely difficult to manufacture by conventional forging processes. U.S. Pat. Nos. 4,007,550 issued Feb. 15, 1977 to V. A. Stepe; 4,071,967 issued Feb. 7, 1978 to G. R. Klett; and 4,182,057 issued Jan. 8, 1980 to G. R. Klett and J. A. Thies, each being assigned to the assignee of the subject invention, teach a replaceable corner tooth that provides means to transfer loads from the leading edge of the tip into the implement and further provides a means to releasably secure the adapter to the implement. However, they each suffer from common problems. More specifically, each of the corner adapters have an outside vertical portion and an inner strap that interact to sandwich a portion of the corner of the implement and must be secured by a bolt or other fastening means. Consequently, during assembly it is necessary for the bolt to be securely tightened in an attempt to insure that the member does not move with respect to the corner of the implement. Since a two strap design is utilized in the above-noted patents, it is necessary, because of loose tolerances, to provide sufficient clearance between the straps so that the corner tooth fits the implement corner under the worst tolerance conditions. The double strap design, with the required clearance, leaves a gap between the sides of the straps and the implement corner sandwiched therebetween. In order to provide a tight connection between the corner tooth and the implement corner, the gap has to be tightly closed by the fastening means (bolt). Many times the torque normally needed for a tight connection is partially or fully used to close the gap thus a "loose" connection results. Consequently, during normal working conditions, the corner tooth can easily move relative to the implement corner thus requiring the bolt to absorb any additional loads as opposed to the additional loads being shared by the bolt and the joint connection. The resulting "loose" connection causes wear in the load transfer pads and creates a lever action that works against the inside strap causing the strap to break. In the situations where the connection appears tight but is not tight due to the large amount of tightening torque used just to close the gap, additional tensile force applied to the bolt under operation may cause the bolt to stretch or yield thus again causing a "loose" connection. Furthermore, since the construction of these designs does not allow them to be produced by a forging process which provides stronger parts, it is normally necessary to produce them by a casting process.
U.S. Pat. No. 3,967,398 issued July 6, 1976 to V. A. Stepe and assigned to the assignee of the subject invention illustrates a replaceable corner tooth that is bolted to the corner portion of the implement by only one side portion of the replaceable corner tooth but suffers from the problem that the construction of this design makes it practically impossible to produce by normal forging processes. Furthermore, the load transferring characteristics of this design are primarily introduced into the bolts without having additional load transferring means to carry either tensile or shear forces on the bolts.
U.S. Pat. No. 4,047,312 issued Sept. 13, 1977 to V. A. Stepe and assigned to the assignee of the subject invention illustrates a design that is bolted both to the side of the implement and also to the bottom portion of the implement. This design also proves to be more difficult to manufacture and creates more of a problem to mate with the corner of the bucket when the components of the bucket corner are welded one to the other. The tolerances on the corner of the bucket are much more difficult to maintain when the components of the bucket corner are welded together.
The present invention is directed to overcoming one or more of the problems as set forth above.